Passage of substances from the blood into the brain and into the cerebrospinal fluid across the blood-brain barrier will be studied utilizing a protein marker, horseradish peroxidase. Proteins have been shown to leak transiently from the blood into specific parts of the brain during prolonged seizures in cats, but the site of this leakage and where the protein is going have not been examined. Horseradish peroxidase will be used to demonstrate the site of the protein-leakage with the electron microscope. Many patients with seizures have transient disorders of consciousness following a seizure which could be related to alterations in the blood-brain barrier.